Marital relationships are one of the most important relationships established in adulthood, and they have significant consequences for psychological well-being. However, Mexican Americans are virtually absent in the close relationship research literature and very little is known about marital satisfaction among Mexican Americans or how it may be related to mental health. The purpose of this longitudinal study is to 1) examine the relationship between marital satisfaction and depression and anxiety among married Mexican American and European American couples; and 2) investigate how marital satisfaction in the first year of marriage is related to depression and anxiety in the third year of marriage. At each time period, ethnic group and gender differences will be assessed. In addition, among Mexican Americans, the relationships between acculturation and acculturative stress and marital satisfaction and mental health will be determined. This study will be one of the first longitudinal investigations of marital satisfaction among Mexican Americans, and one of the first to examine the relationship of marital satisfaction to mental health over time in this group. This study will increase knowledge about contemporary Mexican American couples' relationships; determine whether marital satisfaction is related to psychological adjustment, and clarify how Mexican Americans may differ from European Americans in this respect; and results may have direct applicability to therapeutic interventions to help distressed Mexican American couples. Furthermore, by including an examination of acculturation and acculturative stress in marital satisfaction and mental health among Mexican American couples, this study provides an initial step in development of a social ecological perspective for understanding the marital dynamics of Mexican American couples. Greater knowledge about married couples' relationships is important in light of the pivotal role they play in family stability, children's overall adjustment, and the mental and physical health of partners themselves. This study addresses the NIMH priority of identifying mechanisms that may confer vulnerability to psychiatric illnesses. From a public health standpoint, this research will contribute to reducing the burden of mental disorders for this population by informing the understanding of the relationship between marital distress and mental disorders for this understudied group. It is a first step in future development of early interventions for reducing severity and incidence of mental health problems in Mexican American married couples.